Finally drew my own ref sheet and got enough details figured out. Apologies about the length!

Linear Mathdragon has two forms, anthro and serpentine (or feral), which she can shift between at will.

In both forms, she has silver scales, with white scutes down her chest and tail. She also has two white horns, and two curved white spikes on the back of her neck, pointing downwards. She has a red line from her left shoulder down her arm to the back of her hand, terminating between her ring and middle finger.

Her wings have two segments, with four lines in concentric arcs around each of the two joints. The furthest arc around the outer joint terminates at the wing terminus and the shoulder, and the furthest arc centered on the shoulder terminates at the outer joint and just above the tail. The other arcs are equidistant. If there isn't enough room for the arcs since the wings are folded, then they can be squished together.

Anthro

The most clear difference between the two forms is that Linear has digitigrade legs in her anthro form. Each foot has three claws on it. The other main difference is the lack of curved spikes on the back. In this form, while Linear can still fly, her wings are incorporeal, and can be dismissed. Her tail can also grow or shrink, though she generally keeps it at about a meter. She is slightly below two meters tall in this form.

Serpentine

Linear is much more attuned to the field of linear algebra in this form, and has greater control over the field. Her wings are permanent and corporeal for as long as she stays in her serpentine form, and instead of legs and a tail, she has a long serpentine body, with the spikes on her head and tail now forming an unbroken line. With her tail now being most of her body, she is more able to scale herself, but normally stands between two meters and a more impressive four meters.